African migrants have gathered outside Israel's parliament in Jerusalem, demanding to be recognised as refugees and protesting against the government's policy of long-term detention.

Wednesday's demonstration was "calm", Micky Rosenfeld, Israel's police spokesman, told AFP news agency, adding that police were deployed to keep order. He put the number of protesters at "more than 10,000".

Al Jazeera's Tom Ackerman, reporting from Jerusalem, said: "This is, according to the police, one of the largest assemblies of protest to have been held outside the Knesset.

"It's the fourth day of their strike and they're all saying they have no intention of giving up their struggle.

"Law enforcement has been relatively lenient and there has been no instance of friction or violence."

This week has seen two other protests in Tel Aviv by the migrants, who want the right to work and better treatment from the Israeli government.

Tens of thousands of migrants, most from Eritrea and Sudan, have come to Israel in recent years, either to flee conflict or to seek employment.

"Israel has the lowest refugee recognition rate in the world," our correspondent said.

"The government says these people, no matter what they say about being politically oppressed, are coming here as economic opportunists.

"The government says if they stay, they will affect the future character of Israel. There is no room for compromise."

On December 10, Israel's parliament approved a law permitting authorities to detain migrants without valid visas indefinitely.

More than 300 migrants have been arrested since the new law went into effect, and dozens more have been summoned for detention, the UN refugee agency said.

In a statement issued on Sunday, Walpurga Englbrecht, UNHCR's representative in Israel, criticised the policy of incarceration of migrants, saying it caused "hardship and suffering" and was "not in line with" a 1951 world treaty on the treatment of refugees.

"Placing asylum-seekers in duress that may force them to opt to return without having examined their asylum claims could amount to a violation" of international refugee conventions," Englbrecht said.

Englbrecht also criticised Israel's official description of migrants as "infiltrators", saying most were refugees or deserved international protection.

Source: Al Jazeera and agencies